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Calling
Doctors Leech and Maggot to the O.R.
Bugs
and parasites are making a comeback into modern medicine, and although they have
been used as a means of therapy for thousands of years, they lost their
popularity in the second half of the 20th century only to regain their previous
status as medical wonders during the 1980s. Two such parasites used today are
leeches and maggots. As gruesome as both are conceived, they have been found to
possess numerous advantages in the field of medicine.
The
Practice of Leeching Throughout History
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The ancient Egyptians were the first to use leeches for healing purposes |
The
use of leeches in medicine dates as far back as 2,500 years ago when they were
used for bloodletting in ancient Egypt. All ancient civilizations practiced
bloodletting including Indian and Greek civilizations. In ancient Greek history,
bloodletting was practiced according to the humoral theory, which proposed that
when the four humors, blood, phlegm, black and yellow bile in the human body
were in balance, good health was guaranteed. An unbalance in the proportions of
these humors was believed to be the cause of ill health. Records of this theory
were found in the Greek philosopher Hippocrates’ collection in the fifth
century B.C. Bloodletting using leeches was one method used by physicians to
balance the humors and to rid the body of the plethora.
In
medieval Europe, a number of superstitious ideas and religious philosophies
started to influence the practice of bloodletting. The practice continued on up
until the 19th century. In 1833, bloodletting became so popular in Europe, that
the commercial trade in leeches became a major industry. France, suffering a
deficiency, had to import 41.5 million leeches. The medicinal leech almost
became extinct in Europe due to the extremely high demand for them. Leeches were
collected in a particularly creepy way. Leech collectors would wade in leech
infested waters allowing the leeches to attach themselves to the collector’s
legs. In this way as many as 2,500 leeches could be gathered per day. When the
numbers became insufficient, the French and Germans started the practice of
leech farming. Elderly horses were used as leech feed where they would be sent
into the water and would later die of blood loss.
Leeches
were thought to be able to cure everything from headaches to brain congestion.
They were used to cure obesity, hemorrhoids, nephritis, laryngitis, eye
disorders as well as mental illness. Their use continued on until the 1960s when
their use in medicine was discontinued.
Leeches
in Modern Medicine
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| Leeches were reintroduced into modern medicine in the 1980s |
The
use of leeches in medicine, otherwise known as Hirudotherapy, made its comeback
in the 1980s after years of decline, with the advent of microsurgery such as
plastic and reconstructive surgeries. In operations such as these, one of the
biggest problems that arises is venous congestion due to inefficient venous
drainage. This condition is known as venous insufficiency. If this congestion is
not cleared up quickly, the blood will clot and arteries that bring the tissues
their necessary nourishment will become plugged and the tissues will die. It is
here where the leeches come in handy. After being applied to the required site,
they suck the excess blood, reducing the swelling in the tissues and promoting
healing by allowing fresh, oxygenated blood to reach the area until normal
circulation can be restored. The leeches also secrete an anticoagulant (known as
hirudin) that prevents the clotting of the blood.
The
leech’s saliva is truly extraordinary containing a number of chemical
compounds useful in medicine. These include a local anesthetic that the leech
uses to avoid detection by the host, the anti-coagulant hirudin that can help
prevent heart attacks and strokes, a vasodilator and a prostaglandin that help
reduce swelling. The leech’s gut harbors a bacterium known as Aeromonan
hydrophila. This bacterium aids in the digestion of ingested blood and produces
an antibiotic that kills other bacteria that may cause putrefaction.
Not
only are leeches economically beneficial costing as little as $4.75 to $6.50
apiece, but studies have shown that Hirudotherapy doubles the success rate of
transplanted tissue flaps. This is a much higher success rate than that brought
on by drugs or further surgery.
Hirudotherapy
has proven to be useful for a number of other conditions including
cardiovascular disease, ophthalmology and dermatology. Hirudin is also used in
the treatment of inflammation of the middle ear. Osteoarthritis, which is a
painful condition of the knee, is also thought to benefit from leeching. Studies
performed by researchers from the Essen-Mitte Clinic in Germany have shown that
when leeches were applied to the knees of patients with osteoarthritis, they
helped to alleviate the inflammation and pain associated with the condition.
The
hazards associated with leech therapy include infection, excess blood loss that
may require blood transfusion, the loss of leeches in body orifices and spaces,
and allergic reactions. Some patients find the use of leeches disgusting, which
makes it necessary that they have basic information on the benefit of leeches
before the procedure. The secretion of a local anesthetic by the leech makes the
procedure painless except for the initial attachment phase. They fall off
promptly after they have completed feeding.
Scientists
at the University of Wisconsin-Madison have developed a mechanical leech as an
alternative to real leeches. The synthetic leech mimics the action of the leech
allowing for fresh blood to flow through the wound, but unlike the leech, it is
insatiable and can continue to remove blood for as long as is needed whereas the
leech only feeds for about half an hour.
Maggots
a Good Thing?
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| Wounded soldiers whose wounds were infested with maggots healed better than those that were not infested |
Maggots,
those revolting wormlike larvae of flies, are now once again gaining respect in
the medical field. Their use even has a name, maggot debridement therapy or MDT.
Maggots are efficient healers of wounds. This was recognized centuries ago when
wounded soldiers whose wounds were infested with maggots healed better than
those that were not infested. The reason for this is that the maggots used for
this purpose eat dead tissues and leave the healthy, living tissues alone. They
also excrete substances which inhibit and may even kill bacteria. This is
especially useful in areas with poor blood supply that do not benefit much from
antibiotics that cannot reach the area in adequate concentration to do their
job.
Maggots
have been known for their healing ability since the 16th century. Maggot therapy
continued until the 1930s when their use in therapy was so common that over 300
hospitals in the US alone were using them. In the 1940s antibiotic therapy and
surgical techniques replaced the use of maggots. Their superiority in certain
cases to antibiotics was realized in 1989 when they were recognized to be more
efficient cleaners of wounds than any other non-surgical treatment.
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| Scientists have developed techniques to farm maggots for medical use |
Not
all maggots can be used in medicine; only those that do not burrow under the
patient’s skin and do not eat healthy tissues can be used. They do not
multiply in the wound as they must leave it to pupate or they will die. When the
maggots have completed their job, the doctor simply flushes them out of the
wound. The maggots range from 1 to 2 mm in length when they are one day old and
they reach a length of about 1 cm by their fourth day.
In
order to ensure their sterility, scientists have developed techniques to farm
maggots for medical use. The cost of maggot therapy is typically half as much as
conventional therapy making it a very cost effective procedure. The only
disadvantage of this type of therapy other than the yuck factor is the tickling
sensation felt by some patients.
Sources:
-
Apheresis
from Ancient Medicine to the Practice Today.
Hemapheresis.com.
-
BBC
News, 2001: Leeches
'reduce arthritis pain'.
-
Riverdeep
Interactive Learning, 2003: Bug
Medicine.
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Sohn,
Mia, 1997: Leeches:
Medicine of Old?Emory.edu.
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Biomedical
Scientist, 2000: Worms
in medicine - are they useful? The Institute of Biomedical Science:
Science and General Information.
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Carolina
Biological Supply Company1990: Leeches
in Modern Medicine. Carolina Tips - Volume 52, No. 2
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Marchione,
Marilynn, 2002: Blood-Sucking
Machine May Put Leeches Out of Work. Milwaukee Journal Sentinel.
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Leslie,
Mitch, 1999: Leeches
have returned to the medical mainstream, thanks to their blood-sucking
prowess. Stanford Medicine, Volume 16 Number 3
*
Aisha
El-Awady has a bachelor’s degree in medicine from Cairo
University and is currently working as instructor of Parasitology in the Faculty
of Medicine, while preparing her MA. She may be contacted at aawady@islam-online.net
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